Stephenson, P.& J. Hogan 2006. Cloning and characterization of a ribonuclease, a cysteine proteinase, and an aspartic proteinase from pitchers of the carnivorous plant Nepenthes ventricosa Blanco. International Journal of Plant Sciences167(2): 239–248. doi:10.1086/499284

Thornhill, A.H., I.S. Harper & N.D. Hallam 2008. The development of the digestive glands and enzymes in the pitchers of three Nepenthes species: N. alata, N. tobaica, and N. ventricosa (Nepenthaceae). International Journal of Plant Sciences169(5): 615–624. doi:10.1086/533599